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Strategy to design high performance TiB 2 ‐based materials: Strengthen grain boundaries by solid solute segregation
Author(s) -
Dai FuZhi,
Xiang Huimin,
Zhou Yanchun
Publication year - 2020
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.17018
Subject(s) - grain boundary , materials science , grain boundary strengthening , ceramic , grain size , boundary (topology) , metallurgy , composite material , microstructure , mathematical analysis , mathematics
TiB 2 exhibits a unique combination of excellent properties that make it promising candidate for applications in extreme environments, where retention of strength at high temperatures is essential. Tailoring grain boundary properties by segregation is believed a prominent way to design high‐temperature performance of ceramics. In this work, segregation tendencies of solute elements, including Sc, Y, Zr, Hf, V, Nb, Ta, Cr, Mo, and W, in TiB 2 grain boundaries and the strengthening/weakening effects induced by segregations are investigated by first‐principles calculations. The results reveal that small atoms tend to segregate to grain boundary sites with local compression strains, while large atoms prefer grain boundary sites with local expansion strains. Deteriorated grain boundary strength is usually caused by additional expansion strain induced by segregation, while improved grain boundary strength results from either enhanced local bonding induced by segregation of small atoms or increased fracture strain due to segregation of large atoms. Cr and V, especially Cr, exhibit strong segregation tendency and improvement on grain boundary strength, which provides useful guidelines for the design of high performance TiB 2 ‐based materials.